This is weird, but I’ve got this mass in one of my testicles that feels like a bag of worms. Is it cancer?

No, it’s highly unlikely to be cancer, though, of course, you should get properly diagnosed. You probably have a fairly common condition called varicocele (var-i-ko-seal). This is a bundle of enlarged veins in the scrotum. In varicocele, tiny valves in the veins don’t work well, so the blood collects and swells the veins. This is usually painless and is not a medical emergency. But the extra blood in your scrotum can cause problems. The blood warms the testes unnaturally. This interferes with the cells that manufacture sperm, which are extremely temperature-sensitive. It can also lower your testosterone level. The good news: varicoceles are one of the simplest things to fix surgically, and success rates are high.